HS-40

To reach the PCB you have to remove the bottom black piece of the gray case. It is glued with a soft adhesive, so simply pull out with a fingernail. Below this you can find one of the two screws. The upper black piece is now unlocked, and you only have to remove it to see the second screw. Now you have opened the case. Remember where the knots of the cables are, and pull out the PCB. You have to swap the red and white wires as seen in the picture (click on the image for full size).

You have to change the gain of the output in alsamixer from 80% to 95% due to different sensitivity (dBm/mW) of headphone speakers. Microphone works perfectly. Button may work (not tested).

HS-40

To reach the PCB you have to remove the bottom black piece of the gray case. It is glued with a soft adhesive, so simply pull out with a fingernail. Below this you can find one of the two screws. The upper black piece is now unlocked, and you only have to remove it to see the second screw. Now you have opened the case. Remember where the knots of the cables are, and pull out the PCB. You have to swap the red and white wires as seen in the picture (click on the image for full size).

You have to change the gain of the output in alsamixer from 80% to 95% due to different sensitivity (dBm/mW) of headphone speakers. Microphone works perfectly. Button may work (not tested).